The present invention relates to a novel spectrophotometer particularly useful, but not limited to, soluble materials.
Spectrophotometry concerns itself with the measurement of the transmission or reflection of radiant energy by a body in comparison to a standard. Prior spectrophotometers generally fall into two classes: variable wavelength and fixed wavelength types. Fixed wavelength spectrophotometers have good sensitivity but lack the ability to quickly utilize a multiplicity of narrow spectral bands to analyze a sample. Many chemical compounds are transparent to certain bands of electromagnetic spectrum while being absorbent to other bands of the same. Existing variable wavelengths spectrophotometers possess the advantage of using many bands for detection, but require too great a time period to accomplish this task.
A recent innovation in the art of spectrophotometry involves the use of white light being passed through the sample and dispersed into a spectrum. Each element of a linear array of detectors then resolves a narrow portion of the spectrum. The resultant data is processed and provides an accurate depiction of spectral absorbance of the sample being analyzed. However, the linear array is quite expensive and requires passing a high intensity of white light through the sample. The brilliance of the white light tends to adversely effect the solution being analyzed, ie: photo chemical reactions and the like.
Recent art also includes spectrophotometers which utilize oscillating mirrors or gratings to rapidly scan the spectrum through the sample and detector. In such systems, the light transmission at a particular wavelength is derived by sampling the detector output at a precise time during the oscillation, ie: the wavelength measured is related to time. Due to the short sampling time at a particular wavelength the signal to noise ratio from such systems is too low for high performance liquid chromatography use. This system has poor wavelength accuracy and, therefore, exhibits poor reproducibility.
There is a need for a spectrophotometer which is able to quickly employ a plurality of wavelengths of the electromagnetic spectrum to analyze liquid or gas solutions.